Electric welding was introduced in 1940s. Aluminium welding has been in prominence since 1970. There are several types of welding like Arc welding and Manual metal arc is a common process where the workers are exposed to the fumes. Carbon arc, Cold welding, Electron beam welding, Flux core arc welding, Gas welding, Gas metal arc welding, Gas tungsten arc welding, Shielded metal arc welding, Plasma arc welding, Laser beam welding are the other welding processes where workers are exposed to metal fumes.
The welding workers have a high exposure of metal fumes and the exposure depends on place, confined space, workshop or open air. The metal fumes depend on not only the Aluminium but also the process involved which may produce gases like acetylene, carbon monoxide, oxides of nitrogen , ozone, phosgene and tungsten. The metal fumes primarily enter the human system by inhalation route namely Respiration.. The deposition of these inhaled metallic particles is influenced by its physical and chemical properties and a variety of host factors. In the lungs, these particles produce a variety of reactions depending on the concentration, duration of the exposure of the particles, and degree of exposure. All Metallic particles greater than 10 are deposited on the Mucous membrane in the nose and pharynx. Particles between 3m and 10 m are deposited throughout the trachea of the lungs. Particles less than 3m are deposited in the alveoli and cause serious hazards. These particles have a fair chance of being carried into the blood stream and cause Hepatotoxicity and Nephrotoxicity.
Health Hazards of Aluminium fumes :
Hazards of Aluminium fumes have been well documented in various scientific journals. The health hazard assessment is done by sampling and analysis. Sampling has been well prescribed by the Draft British Standard (DD54) for breathing zone and background samples. Chemical analysis techniques for milligram amounts of fume obtained are outlined in DD54; part I.(Moreton,1982)
Aluminium work related Asthma has been established by characteristic patterns of repeated peak flow measurements supported by changes in methacholine responsiveness in workers with work related asthma (Konyerud, 1994).A recent study by keith Harrison of the Queens land Fertility group, Australia has proved the testicular toxicity of such Chemicals in male workers.
Studies have also proved that exposure of workers to these metal fumes aged between 20-64, admitted to 11 hospitals in England during the period between 1996-1999, caused health hazards and is a classic case of occupational hazard of metal fume exposure (Palmer, 2003). Further studies on 27 welders with long-term exposure to these metal fumes revealed a reversible increase in the risk of Pneumonia. In the sputum, cell counts, soluble levels of the metal, levels of Interleukin-8, tumour necrosis factor-, myeloperoxidase, metalloproteinase -9, Immunoglobulin (Ig)A, 2-macroglobulin and unsaturated metal binding capacity were analyzed and in the blood samples, evidence of neutrophil activation and IgG pneumococcal antibodies were analyzed. The studies concluded that the local inflammatory response was affected by chronic exposure (Palmer,2006).
All welding workers thus, are exposed to acute or chronic respiratory disease. Welding fumes cause